1. Field of the Invention
The invention relates to an activated carbon filter apparatus for a motor vehicle.
2. Description of the Related Art
Activated carbon filter apparatuses have been disclosed in motor vehicles to filter vapors that contain hydrocarbons and to ensure that the hydrocarbons cannot escape from the tank and into the surroundings. The hydrocarbons are adsorbed by the activated carbon and are retained as a result.
During operation of the internal combustion engine, the loaded activated carbon of the activated carbon filter apparatus can then be flushed, and the desorbed hydrocarbons can be fed to the internal combustion engine and burned. To this end, fresh air can be introduced through a fresh air opening into the housing of the activated carbon filter apparatus on account of a vacuum from the intake cycle of the internal combustion engine, and the hydrocarbons can be guided to the internal combustion engine and burned as a result of the flushing.
The activated carbon filter apparatus usually has two regions that are filled in each case with activated carbon. The first region has mechanically prestressed activated carbon for adsorbing the hydrocarbons. The second region follows the first region and has an activated carbon filling that absorb the hydrocarbons that exit from the first region at a standstill of the motor vehicle. The activated carbon and/or activated carbon structures usually are configured, for example, as honeycomb structures. They are relatively expensive and should therefore be avoided.
U.S. Pat. No. 7,086,389 B2 discloses an activated carbon filter apparatus that has two volumes filled with activated carbon and connected to one another via a connection at the top. As a result, a relatively short path exists for the hydrocarbons and impairs adsorption.
It is an object of the invention to provide an activated carbon filter apparatus that is improved in comparison with the prior art and can be manufactured inexpensively.